Pusher leg arrangement for rock drills



April 12, 1966 c EKwALL 3,245,484

PUSHER LEG ARRANGEMENT FOR ROCK DRILLS Filed Nov. 21, 1961 2 Sheets-Sheet l 7 i if; i 34 3.9 g 33 270 M Fig.2 KM A April 12, 1966 c. G. B. EKWALL PUSHER LEG ARRANGEMENT FOR ROCK DRILLS 2 Sheets-Sheet 2 Filed NOV- 21, 1961 United States Patent 15 .Claims oi; 173%153);

This inventionrelates generallyto ro clc drills and more specifically to a pusherleg-arrangement for rock drills of the pivoted pressure fluid operated expansible pusher leg type, having improved-means for pivotally attaching the drilling tool to the pusher leg. 4

One object of the invention is togprovide a pusher leg arrangement for rock drills which for improved transportation and servicing conditions-is readily and freely separable at the pivotal connection between the pusher leg and the drilling tool. Another object of the invention is to provide a pusher leg arrangementfor rock drills which in connection with such separation may be divided into two fully assembled components without the use of any kind of fastening elements to be separated fror'nsaid components. Another object of the invention is to provide a pusher leg arrangement 'for rock drills which as soon as the pusher leg and the drilling tool are pivotally' a'ssembled automatically receives a predetermined resistance to relative pivotal movement between said drilling tool and said pusher leg about the pivotal connection. Another more specific object of 'the invention is to provide in a pusher leg arrangement for rock drills a bayonet connection co-axial with the transverse hin e connection between the pusher leg and the drilling 'tool which permits free separation of said drilling tool and pusher leg in a certain tilt position while efliciently keeping the hinge connection assembled and under a predetermined resistance to relative ivotal movement in other tilt i osidens between said drilling tool and said pusher l'e'g. A still further object of the invention is to provide a pusher leg arrangement for rock drills in which enreient pressure fluid conducting means are arranged inthe' hingeconne'ction between the drillin tool and the pusher leg for conducting pressure fluid therebetvv'e'e'n.

The above and other objects of the invention will become obvious from the following dese'r'iption and from the accompanying drawings in which 'anernhodirn'erit of the invention is illustrated byway of example. It should be understood that this embodiment is only illustrative of the invention and that various modifications may be made within the scope of the claims without departing from the scope of the invention. 7

In the drawings FIG. '1 shows a diagrammatic side view of a pusher leg arrangement fora rock drill accordingto the invention. FIG. 2 is an enlarged sectional view on line 22 i n FIG. 1. 7 FIG. 3 is a fragmentary side view of the drilling tool substantially on line in FIG. 2 FIG. 4 is a sectional view on line 4:4;in'FIG. 3. FIG. 5 is a fragmentary side view of the upper extremitysof the pusher leg intended for cooperation with the portion of the drilling tool shown in FIG. 3, and FIG. 6 is a side view corresponding to FIG. 1 but showing thepusher leg arrangement resting on the ground and ready for free separation of the pusher leg from the drilling tool or for being swung upward into assembled hinged interconnectron.

The pusher leg arrangement for rock drills illustrated in the drawings consists of a pressure fluid operated drilling tool 11 preferably a hammer drill, which by'nieans of 'a transverse hinge connection 11 is tiltably mounted on the upper extremity of a conventional pressure fluidoperated pusher leg 12. The pusher leg 12 maybe of any suitable type and is in FIG. l illustrated diagrammatically as 3,245,484 Patented Apr. 12; 1966 having a cylinder housing 13 in which a piston 14 defines lower and upper working chambers 15; 16, respectively. The piston 14 is provided with a pistonrod 17 protrud ing out of the cylinder housing 13 and carrying at its free end a foot piece 18 intended to rest on the ground.

The drilling tool 10 which is provided at its rear with a grasping handle 19 for the directing and guiding of the pusher leg arrangement during work. and carries a drill steel 20, is preferably also equipped with eontrotme ns for controlling the new of pressure fluid to and from the pusher leg 12. To'this end there may be provided on the drilling tool itl 'as diagrammatically indicated in FIG. 1,

"a reduction valve 21 operable by a handle 22 and a slide fluid supply line 25. According 'to FIG.- 1 in the illustrated position of the slide valve 23 there is established a communication 26 from the throttle valve '24 via the reduction valve 21, the slide valve '23 and the hin e connection 11 to the upper working chamber 16, which cham ber by manipulation of the handle 22 of the reduction valve 2-1 may be supplied with fluid at a pressure reduced at will in order to provide for efficient feeding of the drilling tool forwardly by extension of the pusher leg 12. Simultaneously therewith a communication 27 via the hinge connection 1-1 and the slide valve 23 ':o'nnects the lower working chamber '15 on the pusher leg to atmosphere. In order to contract the pusher leg the pressure fluid supply to the pusher leg preferably may be reversihly arranged by means of the slide valve 23, which in another position; not shown, vents the upper working chamber 16'via the communication 26 and connects a direct passage 28- from the throttle valve to the communication- 27, i.e. to 'the lower working chamber 15 or the pusher leg for'contracting-the leg. y

In connection with the general arrangement of the drilling tool andthe pusher leg described above-there is provided according to the invention a releasable hinge connection 11 between-the two components in question. To this end the upper extremity of;- the pusher leg 12 carries an arm 30 extending at one side thereof upwardly from the cylinder housing 13 at an acute angle. A transverse pivot providing element or trunnion 31 is firmly conneoted at one end to the arm 30 by means of a tapered connection 32 firmly secured axially by means of a tape'red lock nut 33 bearing against the arm 30 and in threaded engagement with an end ortion 34 of the trunnion 31. The tapered connection 32 may be secured against rotation by means of an axial pin 29. Adjacent to the tapered connection 32 an annular shoulder or abut- 'ment 35 is provided on the arm 30. The trunnion 31 has a cylindrical intermediate ortion 36 extending between the abut'nrent35 anda flange 37 on the trunnion. Outwardly of the flange 37 the trunnion 31 is formed with a co-axial reduced cylindrical portion 38 carrying at its free 'en'd radial opposed abutments 39.

Slidably and pivotally arranged on the cylindrical intermediate portion 36 of the trunnion 31 is a tapered pivot provid ng element or bushing 40, having its tapered .portion covered by a rubber lining 41 suitably appliedthereto, for example by vulcahizing. Between the bushing 40 an'd the abutment 35 there is placed an elastically compressible rubber ring 42 around the trunnion '31. A washer 43 is provided on the trunnion 31 in line with the rubber ring 42 for frictional contact with the abutment 35. The tapered bushing 40 is prevented from sliding oil axially from the-cylindrical portion 36-bythe'fiange 37 whenthe rubber ring 42 is in its expanded state.

. The drilling tool is provided at an intermediate portion thereof with a transverse boss 45 and a tapered transversely extending hole 46 therein is intended for cooperation with the correspondingly tapered rubber covered portion 41 of the bushing 40 on the trunnion 31 of the pusher leg 12. As a co-axial continuation of the hole 46 there is provided a bore 47 at one end of the boss 45 and firmly fitted into said bore is a locking member 48 retained against rotation with respect to the bore 47 by means of a locking pin 49. The locking member 48 is provided with an axial key opening 50 intended for insertion of the reduced cylindrical portion 38 together with its opposed abutments 39 in a certain angular position of said abutments. As shown in FIG. 6 theangular interarrangement of the abutments 39 and the key opening 50 is such, that the drilling tool 10 has to be tilted to an extreme downward-forward position with respect to the pusher leg 12 in order to bring the key opening 50 into alignment with the abutments 39. The locking member 48 is formed with a diametrically extending V-shaped recess'51 forming diametrically opposed axial cam surfaces 52, 53 on the' locking member 48; The depth of the V-shaped recess is preferably such that the abutments 39, when inserted into the key opening 50, will be about level with the cam surfaces 52, 53 when axial contact is established between the bushing 40 and the corresponding tapered hole 46 in the boss 45.

Supposing the pusher leg and the drilling tool to be in separated state, the drilling tool 10 with the drill steel removedis grasped by the handle 19 and kept in an inclined upstanding position on the ground as illustrated in FIG. 6. Thereupon the trunnion 31 of the pusher leg 12 to be hingedly connected with the drilling tool 10 is pushed into the tapered hole 46 of the boss 45 of the drilling tool until the tapered surface of the bushing 40 contacts said hole, in which position the abutments 39 extend into the key opening 50 and are level with the cam surfaces 52, '53. By means of a quick upward backward pull of the handle 19 the drilling tool 10 thereupon is lifted from the ground tilting with respect to the pusher leg 12 from the extreme forward tilt position shown into some intermediate tilt position, for example the position of FIG. 1. Such tilting of the drilling tool 10 causes the cam surfaces 52, 53 to penetrate under the abutments 39 which in bayonet lock manner slide upward along said cam surfaces 52, 53 causing a displacement of the locking member 48 together with the boss 45 and the bushing 40 axially in the direction of the opposed abutment 35 until, finally, the abutments 39 ride up on the end surface of the locking member 48. The axial movement of the bushing 40 causes acompression of the compressible elastic rubber ring 42, which urges the aligned friction washer 43 into frictional contact with the abutment 35. In the final assembled position of the parts involved the friction washer 43 receives a predetermined invariable compression dependent upon the added width of the locking member 48 of the boss and the bushing 40 as compared to the distance between the washer 43 and the abutments 39. The rubber lining 41 and ring 42 prevent in compressed state relative movement and wear between the washer 43, the bushing 40, and the boss 45. Tilting of the drilling tool on the trunnion 31 during work of the pusher leg arrangement thus results in free relative motion of the bushing 40 and the locking member 48 with respect to the trunnion 31 and relative motion against a predetermined invariable resistance between the friction ring 43 and the adjacent abutment 35.

For quick separationthe drilling tool 10 is again tilted to the extreme forward-downward position on the pusher leg 13, in which position the abutments 39 will be aligned leg 12, in which position the abutments 39 will be aligned with the key opening of the locking member 48 so that free separation in axial direction along the rubber lining 41 and the abutting tapered hole 46 may be performed. Obviously such forward-downward position is never applied during normal use of the pusher leg arrangement. i

For purposes of convenient leading of pressure fluid to and from the pusher leg through the above indicated communications 26, 27, longitudinal passages 26a, 27a, FIG. 2, are provided in the drilling tool 10 between the tapered hole 46 and the slide valve 23, followed by opposed peripheral grooves and radial perforations 26b, 27b in the bushing 40, longitudinal passages 26c, 27c through; the trunnion 31, and passages 26d, 27d in the pusher leg; 12 leading to the respective working chambers 15, 16. The rubber lining 41 serves as a seal for the grooves 26b, 27b at the tapered surface of the bushing 40 while O-rings 54 tightening against the cylindrical portion 36 of the trunnion 31 are provided inside of the bushing 40.

The embodiment of the invention above described and illustrated in the drawings should only be considered as an example and the invention may be modified in several different ways within the scope of the following claims.

What I claim is:

1. Pusher leg arrangement for rock drills comprising a drilling tool, a pressure fluid operated expansible pusher leg for supporting and feeding said drilling tool, a pair of cooperating pivot-providing elements supported on parts of said tool and said leg providing a transverse hinge connection between said pusher leg and said drilling tool to permit tilting of said tool and said pusher leg in a plane into different angular tilt positions with respect to each other, a friction member co-axially disposed between said pivot providing elements for creating, when placed under compression, a resistance to relative pivotal movement about said hinge connection, and bayonet-lock means co-axial with said pivot-providing elements for permitting free axial separation thereof in one of said tilt positions and for placing when interconnected said friction member under a predetermined invariable compression between said pivot-providing elements in other tilt positions of said drilling tool and said pusher leg.

2. Pusher leg arrangement for rock drills comprising a drilling tool, a pressure fluid operated expansible pusher leg for supporting and feeding said drilling tool, first and second pivot-providing elements supported on parts of said tool and said leg, respectively, providing a transverse hinge connection between said pusher leg and said drilling tool to permit tilting of said tool and said pusher leg in a plane into different angular tilt positions with respect to each other, opposed abutment means fixedly associated with said first pivot providing element to define therebetween an invariable distance, a friction member, elastically compressible means in line with said friction member, and said second pivot providing element, said friction member and said elastically compressible means being interposed between and supported against said abutment means with said compressible means compressed for creating a predetermined invariable resistance to relative pivotal movement about said hinge connection in said different angular tilt positions of said drilling tool and said pusher leg.

3. Pusher leg arrangement for rock drills comprising a drilling tool, a pressure fluid operated expansible pusher leg for supporting and feeding said drilling tool, first and second pivot-providing elements supported on parts of said tool and said leg, respectively, providing a transverse hinge connection between said pusher leg and said drilling tool to permit tilting of said tool and said pusher leg in a plane into dilferent angular tilt positions with respect to each other, opposed abutment means fixedly disposed upon said first pivot providing element at each end thereof to define therebetween an invariable distance, a friction member and elastically compressible means in line with said friction member, said second pivot providing element, said friction member and said elastically compressible means being disposed upon said first pivot providing element and interposed between and supported against said abutment means for compressing said compressible means upon assembly for creating a predetermined invariable resistance to relative pivotal movement about said hinge connection in said different angular tilt positions of said drilling tool and said pusher leg, and cam means disposed at one end of said first pivot providing element and adjacent to one of said abutment means for engaging said second pivot-providing element, said friction member and said elastically compressible means compressing them against said second abutment means during transition from one angular tilt position of said drilling tool and said pusher leg to another tilt position.

4. Pusher leg arrangement for rock drills comprising a drilling tool, a pressure fluid operated expansible pusher leg for supporting and feeding said drilling tool, a pair of cooperating pivot-providing elements supported on parts of said tool and said leg providing a single transverse hinge between said pusher leg and said drilling tool to permit tilting of said tool and said pusher leg in a plane into different angular tilt positions with respect to each other between an extreme backward tilt position and an extreme forward tilt position of said drilling tool, and a pair of cooperating bayonet-lock means co-axial with said pivot-providing elements and with one non-rotatably affixed to said rock and the other non-rotatably aflixed to said pusher leg permitting free separation of said drilling tool from said pusher leg in said extreme forward tilt position into only two parts.

5. Pusher leg arrangement for rock drills comprising a drilling tool, a pressure fluid operated expansible pusher leg for supporting and feeding said drilling tool, pivotproviding elements supported on parts of said tool and said leg providing a transverse hinge connection between said pusher leg and said drilling tool to permit tilting of said tool and said pusher leg in a plane into different angular tilt positions between an extreme backward tilt position and an extreme forward tilt position of said drilling tool, a compressible friction member disposed upon said transverse hinge connection between said pivot providing elements for creating, when placed under compression, a resistance to relative pivotal movement about said hinge connection, bayonet lock means disposed on said transverse hinge connection and co-axial with but spaced from said pivot providing elements for permitting free separation of the drilling tool from said pusher leg in said extreme forward tilt position and for engaging said friction member and keeping it under a predetermined invariable compression in other tilt positions of said drilling tool and said pusher leg, and cam means on said hinge connection for engaging said bayonet-lock means for placing said friction member under said compression during transition from said extreme forward tilt position to adjacent tilt posit-ions of said drilling tool and said pusher leg.

6. In pusher leg apparatus of the character described for supporting and feeding rock drills and having a drilling tool and a pressure fluid operated expansible pusher leg and a hinge connection transverse to said tool and connecting said pusher leg thereto permitting tilting of said tool and said pusher leg into different angular positions with respect to each other, the combination which comprises a pair of cooperating bayonet lock members on said hinge connection, one being fixedly and non-rotatably connected to said drilling tool on one part of said transverse hinge connection and the other fixedly and nonrotatably connected to said pusher leg on the other part of said transverse hinge connection for permitting free separation of said drilling tool from said pusher leg at only one of said tilt positions.

7. In pusher leg apparatus of the character described for supporting and feeding rock drills and having a drilling tool and a pressure fluid operated expansible pusher leg and a hinge connection transverse to said tool and connecting said pusher leg thereto permitting tilting of said tool and said pusher leg into different angular positions with respect to each other, the combination which comprises a pair of cooperating bayonet lock members on said A 6 hinge connection, one being fixedly connected to' said drilling tool on one part of said transverse hinge connection and the other fixedly connected to said pusher leg on the other part of said transverse hinge connection for permitting free separation of said drilling tool from said pusher leg at only one of said tilt positions, and means in said transverse hinge connection for creating a predetermined constant resistance to relative pivotal movement about said hinge connection upon interconnection of said lock means.

8. Apparatus as recited in claim 6 in which said tilt position for free separation of said pusher leg from said tool is the extreme forward tilt position of said drilling tool on said pusher ieg with said drilling tool at an acute angle to said pusher leg, whereby the part of said bayonet lock member on said pusher leg becomes positioned with respect to the part on said drilling tool for free separation of the two parts. a

9. In apparatus of the character described for readily disconnecting the drilling tool of a rock drill from the supporting and feeding member thereof into only two pieces and having a drilling tool and a supporting and feeding member, the combination which comprises a boss disposed on said drilling tool, a trunnion disposed on said supporting and feeding member extending transversely of said feeding member and said drilling tool and adapted to be pivotally connected to and axially removable from said boss, a bushing rotatably disposed around said trunnion for interfitting mating engagement with said boss and coaxially therein, and a pair of cooperating bayonet lock members, one being rigidly connected to said trunnion and the other to said boss coaxially with said trunnion for holding said boss and said bushing around said trunnion in cooperating non-rotatable coaxial relationship in different angular positions of said trunnion with respect to said boss and said bushing therein and for permitting free axial separation of said trunnion and said bushing from said boss in one angular position of said trunnion with respect to said boss.

10. Apparatus as recited in claim 9 which also includes elastically axially compressible means disposed around said trunnion axially between said bushing and said feed ing member for compression upon interconnection of r I said bayonet lock members for creating by said compression a thrust on said bushing and said bayonet lock member for holding said bushing in said boss.

11. Apparatus as recited in claim 10 and including pressure fluid conducting means extending between said drilling tool and said feeding member through said trunnion and said bushing, an annular sealing means for said fluid conducting means disposed between said bushing and said trunnion providing sealing protection for said fluid conducting means in an unexposed position in said hinge connection.

12. In pusher leg apparatus of the character described for supporting and feeding rock drills and having a drilling tool and a pressure fluid operated expansible pusher leg, the combination which comprises a hinge connection transverse to said tool and disposed between said tool and said leg and including a trunnion and a bushing rotatably journaled on said trunnion to permit tilting of said tool and said leg into different angular tilt positions in a plane with respect to each other, pressure fluid conducting means to conduct fluid from said tool to said leg including passages in said trunnion and said bushing, a compressible friction member disposed axially between said bushing and said trunion, a pair of cooperating bayonet lock members coaxial with said bush-ing and said trunnion and nonrotatably associated therewith for permitting free separation of said tool and said leg along said connection in one of said tilt positions but for keeping said friction member under a predetermined axial compression when interconnected in others of said tilt positions creating a resistance to relative pivotal movement. about said hinge connection.

13. In pusher leg apparatus of the character described for supporting and feeding rock drills and having a drilling tool and a pressure fluid operated expansible pusher leg and a separable hinge connection transverse to said tool connecting said pusher leg thereto permitting tilting of said tool and said pusher leg into, different angular positions with respect to each other in a plane, the combination which comprises a pair of cooperating pivot elements having cooperating bearing surfaces therebetween, said elements providing the pivotal portion of said hinge connection and being disposed on said pusher leg to form a trunnion thereon, a boss on said tool for cooperating nonrotatable engagement with one of pivot elements of said trunnion for formingsaid separable portion of said transverse hinge connection, a pair of cooperating bayonet lock members one of which is rigidly connected to the other of said pivot elements of'said trunnion and the other of which is rigidly connected to said boss and coaxia lly disposed therewith to maintain them in cooperating relationship but permitting free separation of said boss and said trunnion in one of said tilt positions, said pair of bayonet lock members being separated from but coaxial with said cooperating surfaces of said pivot elements and said separable portions of said hinge connection.

14. In pusher leg. apparatus of the character described for supporting and feedingrock drills and having a drilling tool and. a pressure fluid operated expansible pusher leg and a separable hinge connection transverse to said tool connectingsaid pusher leg thereto permitting tilting of said tool and said pusher leg into different angular positions with respect to each other in a plane, the combination which comprises a pair of cooperating pivot elements having cooperatingbearing surfaces therebetween, said elements, providing the pivotal portion of said hinge con nection and forming a trunnion therefor, a boss on said connection for cooperating non-rotatable engagement with one of said pivot elements of said trunnion for forming said separable portion of said transverse hinge connection, a pair of cooperating bayonet lock members one of which is rigidly connected to theother of saidpivot elements of said trunnion and the other of which is rigidly connected to said boss and coaxially disposed therewith to maintain them in cooperating relationshipbut permitting free separation of said boss and said trunnion in one of said tilt positions, said pair of bayonet lock members being sepa-. rate from but coaxial with-said cooperating surfaces of said pivot elements and said separable portions of said hinge connection.

15. In pusher leg apparatus of the character described for supporting and feeding rock drills and having a drill-. ing tool and a pressure fluid operated expansible pusher leg and a hinge connection transverse to said tool connecting said pusher leg thereto permitting tilting of said tool and said pusher leg into different angular positions with respect to each other, the combination which cornprises a pair of cooperating pivot elements having cooperating bearing surfaces therebetween, said elements providing the pivotal portion of said hinge connection and being disposed on said pusher leg to form a trunnion thereon, aboss on said tool for cooperating engagement with said trunnion forming said separable portion of said transverse hinge connection, a pair of cooperating bayonet lock members one eachv of which is rigidly connected to said trunnion and said boss and coaxially disposed therewith to. maintain. said boss and said trunnion in cooperating relationshipv but permitting free separation thereof in one of saidtiltpositions, said pair of bayonet lock members being separate from but coaxial with said cooperating surfaces of said pivot elements and said separable portions of said hinge connection, and means on said transverse hinge connection responsive to interconnection of said cooperating bayonet lock members for maintaining said cooperating surfaces of said pivot elements in a relationship of predetermined, constant resistance to relative pivotal movement about said. hinge connection during all said different. angularpositions of tilt except said one permitting separation of said separable portions.

References Cited by the Examiner UNITED STATES PATENTS 221,285 11/1897 Cooper 285191 2,265,267 12/1941 Cowles 285-402 2,525,879 10/ 1-950 Far-ishet al 285190 2,908,482 10/ 1959 Curtis et a1 -424 2,929,611 3/1960 Read 175-124 3,064,741 11/ 1962 Morrison 175124 3,065,806 11/1962 Thompson 175-124 3,085,638 4/1963 Larcen. 173-36 FOREIGN PATENTS 23,883 1902 Great Britain.

BROUGHTON G. DURHAM, Primary Examiner. CHARLES E. OCONNELL, Examiner. 

6. IN PUSHER LEG APPARATUS OF THE CHAMBER DESCRIBED FOR SUPPORTING AND FEEDING ROCK DRILLS AND HAVING A DRILLING TOOL AND A PRESSURE FLUILD OPERATED EXPANSIBLE PUSHER LEG AND A HINGE CONNECTION TRANSVERSE TO SAID TOOL AND CONNECTING SAID PUSHER LEG THERETO PERMITTING TILTING OF SAID TOOL AND SAID PUSHER LEG INTO DIFFERENT ANGULAR POSITIONS WITH RESPECT TO EACH OTHER, THE COMBINATION WHICH COMPRISES A PAIR OF COOPERATING BAYONET LOCK MEMBERS ON SAID HINGE CONNECTION, ONE BEING FIXEDLY AND NON-ROTATABLY CONNECTED TO SAID DRILLING TOOL ON ONE PART OF SAID TRANSVERSE HINGE CONNECTION AND THE OTHER FIXEDLY AND NONROTATABLY CONNECTION TO SAID PUSHER LEG ON THE OTHER PART OF SAID TRANSVERSE HINGE CONNECTION FOR PERMITTING FREE SEPARATION OF SAID DRILLING TOOL FROM SAID PUSHER LEG AT ONLY ONE OF SAID TILT PORTIONS. 